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The Detection and Characterization ofThe Detection and Characterization of NanoparticlesNanoparticles in the Environmentin the Environment
John Scalera, U.S. EPA Office of Environmental Information,
OIAA/ EAD July 12, 2006
An Overview on NanotechnologyAn Overview on Nanotechnology Detection and Analysis MethodsDetection and Analysis Methods
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Areas to be PresentedAreas to be Presented
z What Are You Looking For?
z Analytical Hurdles
z Unique Properties, Analysis, and Source Identification
z Environmental Analysis Methods
z Development of Standards
z Additional Information Sources
DISCALIMER: The identification of manufacture supplied information or their products as a part of this presentation is for information purposes only and should not be perceived as an endorsement by the
EPA.
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 121
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
What Are You Looking For ?What Are You Looking For ?z Manufacturer’s Characterization Information:
z Organic versus inorganic structure/ chemical composition/molecular weight
z Solubility
z Type (fullerenes, single-walled nanotubes (SWNTs),quantum dots, dendrimers, complexed organics, contain a metal element )
z Particle Size Distribution
z Particle Surface Area
z Zeta Potential
z Use (pharmaceutical, gasoline additives, material properties enhancement, water purification)
z Specific industries/locations involved in production
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What Are You Looking For ? (cont.)What Are You Looking For ? (cont.)
z Environmental Transformation:
z Degradation (biotic and abiotic)
z Oxidation to a more complex state
z Morphological changes
z Agglomeration/coagulation
z Aggregation
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 122
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Environmental Analysis HurdlesEnvironmental Analysis Hurdles
– Trace levels of the nanoparticles of interest
– Other nanoparticles of non-interest (natural, incidentally formed)
– Particle size changes (agglomeration, aggregation, condensation)
– Chemical Impurities/Interferences
– Vaporization of Organics During Sample Preparation and Analysis
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Environmental Analysis HurdlesEnvironmental Analysis Hurdles
– Static charges
– Extraction Efficiencies (sequestration)
– Aquatic stability due to colloidal formations in the environment
– Lack of quality control reference materials/surrogates
– Lack of standard analytical methods
– Laboratory contamination/ background levels
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 123
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Unique Properties, Analysis andUnique Properties, Analysis and Source IdentificationSource Identification
z Unique Physical Characteristics – Particle Size – Diffusion Properties – Morphology
Unique Chemical Characteristics – Radioactive Isotope Ratios – Marker chemicals – Elemental Ratio Characterization
z Unique Spectroscopic Properties – Gold particle reflection at nano level – Fluorescence freq.varies with particle size.
z Unique Quantum Effects – Magnetic properties
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Environmental Analysis ProcessEnvironmental Analysis Process
z Sample Collection
z Extraction
z Fractionation/Concentration/Cleanup
z Analysis
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 124
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Environmental Analysis Method TypesEnvironmental Analysis Method Types
z Real-time analysis – single-particle analytical techniques
– ensemble analytical techniques
z Subsequent analysis – single-particle analytical techniques
– ensemble analytical techniques
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Aerosol: Bulk Sample CollectionAerosol: Bulk Sample Collection
z Mechanical Collectors – HEPA filters , ultra-low particle air filters
(down to 5 nms)
z Aerodynamic Mobility Based Collectors – Cyclones (down to about 60 nms)
– Impactors (down to about 60 nms)
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 125
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Aerosols: Isolation ofAerosols: Isolation of NanoparticleNanoparticleFractionsFractions-- Aerodynamic MobilityAerodynamic Mobility
z Inertia Impactors – Particle size = “aerodynamic diameter” – Cascade impactor = multiple impactor
plates in series – Nano- Micro-orifice uniform deposit
impactor (MOUDI), 6 nm limit
z Electrical Low Pressure Impacto(ELPI) Real-time particle counts per size fraction – Incorporates multiple electrometers – Range 7 nms to 10 microns
Cascade Impactor
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Aerosol: Bulk Sample CollectionAerosol: Bulk Sample Collection
z Electrostatic Collectors – Aerosol particles are charged in a chamber then
electro-statically precipitated onto a collecting surface
– Down to 5 nms
z Thermal Precipitators
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 126
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Aerosols: Isolation ofAerosols: Isolation of NanoparticleNanoparticleFractionsFractions--Electrical MobilityElectrical Mobility
z Differential Mobility Analyzer (DMA)
– Particle size = “electrical mobility equivalent diameter”
– 2 nm to 1micron
– Alternate voltage to obtain various nanometer size fractions to outlet slit
z Fast Mobility Particle Sizer (FMPS) Real-time particle counts per size fraction
– Incorporates multiple electrometers
– Range 6 nm to 560 nm TSI Model 3081 DMA
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Aerosols: Particle CountingAerosols: Particle Counting——CPC, CNCCPC, CNC
z Condensation Particle Counters (CPC), or Condensation Nuclei Counters (CNC)
– Detection of particles down to approximately 3 nm
– Supersaturated vapor (water, isopropyl or butyl alcohol)
– Particle grows 100 to 1000 times larger in size.
– Optical detection
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 127
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Aerosols:Aerosols: NanoparticleNanoparticle SizeSize CharacterizationCharacterization——Diffusion TechnologyDiffusion Technology
z Diffusion Batteries – Particles demonstrating increasing diffusion
character with smaller particle sizes. z Aerosol flows through a diffusion battery
consisting of a series of fine capillaries or wire-mesh screen grids. Smallest particles exit first where they are counted using CPC/CNC.
z Sensitivity down to about 3 nanometers
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Mass AnalysisMass Analysis
z Mass of nanoparticle 10-18 gram
z Weighing of collection filters possible concentration factor significant collection time period controlled env. (e.g, humidity control)
z Piezoelectric crystal balance z Quartz Crystal—alteration in resonance frequency as particles attach z Sensitivity limits is approximately 1 nanogram
z Beta Meter z Measures the change in detected beta radiation through a filter as
particles deposit on the filter. z Particle mass is proportional to the degree of signal attenuation z sensitivity is approximately 25 ug per cm2
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 128
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Mass Analysis(cont)Mass Analysis(cont)
z Calculating an approximate mass of a particle fraction:
– particle count for a size fraction
– assume shape; get a particle volume
– use a known or an approximate particle density
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Aerosol Analysis: Single Particle Analyses,Aerosol Analysis: Single Particle Analyses, Size and Chemical CompositionSize and Chemical Composition
z Aerosol Time-of-Flight Mass Spectrometry (ATOFMS)
– Real-time Analysis
– Range = 30nm to 3 um.
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 129
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
NonNon--Aerosol Bulk SamplesAerosol Bulk Samples
z Grab Samples: water/soils/sediments
– Agglomeration/Coagulation Issues
• Sonication
• Dispersing Agent
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Bulk Samples Analysis:Bulk Samples A Samplenalysis: Sample Preparation/ExtractionPreparation/Extraction
z Solid or Liquid Matrix: sieves—40 micron limit
z In a liquid matrix: filtration, centrifugation
z Liquid/Liquid Extraction: organic vs water soluble fractions; separatory flask
z Soxhlet Extraction: extraction of organic soluble fraction from sediments or soil.
z Solid Phase Extraction: extraction of analytes from liquid fraction
z Ion Exchange Columns
z Supercritical Fluid Extraction (SFE) Mr. John Scalera
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 130
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Bulk Samples Analysis:Bulk Samples A Samplenalysis: Sample Preparation/Extraction/FractionationPreparation/Extraction/Fractionation
Filtration/Ultrafiltration Techniques (samples inliquid medium) – Variable Cut-off size membranes – Stirred filtration cells – Continuous loops for maximized extraction and
concentration /diafiltration techniques
Centrifugation/Ultracentrifugation – Based upon particle density – Centrifugal filters or membranes
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Isolation ofIsolation of NanoNano Sample FractionsSample Fractions from Collected Samples (cont)from Collected Samples (cont)
z Field Flow Fractionation (FFF) – Based upon particle diffusion; the diffusion
coefficient is inversely proportional to particle size
– Approximately 1nm to a few micrometers z Asymmetric Flow Field Flow Fractionation (AF4) z Gravitational z Thermal z Magnetic z Electrical
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 131
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Isolation ofIsolation of NanoNano Sample FractionsSample Fractions from Collected Samples (cont.)from Collected Samples (cont.)
z Asymmetric Flow Field Flow Fractionation ( AF4)
Diagram Courtesy of Postnova Analytics at www.postnova.com
Channel height =100 to 500 um
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Isolation ofIsolation of NanoNano Sample FractionsSample Fractions from Collected Samples (cont)from Collected Samples (cont)
z Field Flow Fractionation (FFF)
– Greater the particle density, the lower the fractionation particle size limit
– 0.2000 mg mass in 20 to 100 uls injected
– One hour analysis time at 1 to 2 mls of elutent per minute
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 132
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Sample Fractionation & Analysis:Sample Fractionation & Analysis: ChromatographyChromatography
z Chromatographic Technologies – High Pressure Liquid Chromatography (HPLC)
z Size exclusion chromatography-separation based on particle size, physical impedance
z Ion Chromatography-separation based upon ionic properties of the particle
– Supercritical Fluid Chromatography z Separation based on solvency in supercritical fluid
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Analytical Techniques: Particle SizeAnalytical Techniques: Particle Size DistributionDistribution
z Dynamic Light Scattering (DLS) or Photon Correlation Spectroscopy (PCS)
z Particle size analysis in liquids z Range less than 5 nm to over 1 micron z Can be used on-line in tandem with fractionation
methods (e.g., HPLC-DLS)
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 133
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Co ed Fraction OffC llectollected Fraction Off--Line Single ParticleLine Single Particle Analysis: Electron MicroscopyAnalysis: Electron Microscopy
z Analysis on a particle by particle basis Scanning Electron Microscopy (SEM) Transmission Electron Microscopy(TEM)
– Energy dispersive X-ray analysis (EDX) – Electron energy loss spectroscopy (EELS)
z Particle size, morphology, chemical composition
Silicon wafer structure Image courtesy of the National Institute of Standards and Technology
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OffOff--Line Single PaLine Single P rticle Analysis:article Analysis: Electron Microscopy (cont.)Electron Microscopy (cont.)
z Collection and preparation challenges: – Loss due to volatilization – Electrostatic forces – Resuspension and uniform deposit of onto analysis
substrate.
z Cost z Time z Highly Skilled Analyst z Statistical Accuracy requires large analyzed
population of particles
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 134
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
OffOff--Line Single PaLine Single P rticle Analysis: Atomicarticle Analysis: Atomic Force Microscopy (AFM)Force Microscopy (AFM)
– Applied in air or liquid mediums
– Uses the interaction of van der Waals forces between the microscopic tip of the AFM and the particle.
– Provides information down to the molecular level
– particle size, morphology
3 micron tall pyramidal tip with a 30 nm end radius
cantilever
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Particle Sizing Methods
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 135
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Surface Area AnalysisSurface Area Analysis
z Surface Area z Epiphaniometer
– Particles exposed to radiation (211Pb),then passed through capillaries and collected onto filters for radiation level analysis (radiation level measure is proportional to particle surface area).
z BET-Method (Brunauer, Emmet, and Teller) [Burtscher] – Measures the amount of gas absorbed onto surface areas.
z TSI Model 3050 “Nanoparticle Surface Area Monitor”
www.TSI.com Mr. John Scalera
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Analytical Techniques: ChemicalAnalytical Techniques: Chemical CompositionComposition
z X-ray Fluorescence (XRF)
z Mass Spectrometry (MS)
z Proton-Induced X-ray Emission (PIXE)
z Inductively Couple Plasma-Atomic Emission Spectroscopy (ICP-AES)
z ICP-Mass Spectroscopy (ICP-MS)
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 136
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Standards Development: ASTMStandards Development: ASTM
z Committee E56 on Nanotechnology – E56.02 Characterization: Physical, Chemical,
and Toxicological Properties – WK8705: Measurement of Particle Size Distribution of
Nanomaterials using Photon Correlation Spectroscopy
– WK9952: Standard Practice for Measuring Length and Thickness of Carbon Nanotubes Using AFM Methods
– WK10417: Standard Practice for the Preparation of Nanomaterials Samples for Characterization
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Standards Development: InternationalStandards Development: International Organization for Standardization (ISO)Organization for Standardization (ISO)
z ISO TC 229 Nanotechnologies – Nov. 2005 inaugural meeting
z WG 1 Terminology and Nomenclature (Canada)
z WG 2 Measurement and Characterization (Japan)
z WG 3 Health, Safety and Environment (U.S.)
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 137
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Standards Development: American NationalStandards Development: American National Standards Institute (ANSI) & U.S. TAG to ISOStandards Institute (ANSI) & U.S. TAG to ISO
TC 229TC 229
z ANSI Nanotechnology Standards Panel
– ANSI-NSP formed in August 2004
– U.S. Tech. Advisory Group (TAG) to ISO TC 229 z ANSI accredited
z July 2005 inaugural meeting
z Workgroups: Terminology and Nomenclature, Measurement and Characterization, Health, Safety and Environment (U.S.)
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Standards Development: Institute ofStandards Development: Institute of Electrical and Electronics Eng. (IEEE)Electrical and Electronics Eng. (IEEE)
z Standard Methods for the Characterization of Carbon Nanotubes Used as Additives in Bulk Materials (P1690TM) (In Progress)
– This project will develop standard methods for the characterization of carbon nanotubes used as additives in bulk materials.
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 138
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
Additional Information Sources: AnalysisAdditional Information Sources: Analysis OverOve viewsrviews
z “Overview of Methods for Analysis Single Ultrafine Particles,” Andrew Maynard. Phil Trans. R. Soc. Lond. A(2000)358, pp 25932610.
z “Nanoparticles and the Environment,” Pratim Biswas, Chang-Yu Wu. J. of Air & Waste Management Assoc., Vol. 55, June 2005.
z “A Review of Atmospheric Aerosol Measurements,” Peter McMurry. Atmospheric Environment, Vol 34, Issues 12-14, 2000, pp 1959-1999.
z “Emerging Issues in Aerosol Nanoparticle Science and Technology” NSF Workshop Report. Workshop held at U.of CA, Los Angeles, June 27-28, 2003.
z “Chapter One: Exposure Measurements.” Chow J., Johann P., et. al. Chemosphere, Vol. 49, Issue 9, Dec. 2002, pp 873-901
z “Research Strategies for Safety Evaluation of Nanomaterials. Part VI. Characterization of Nanoscale Particles for Toxicological Evaluation,” Kevin Powers, Scott Brown, et al. Tox. Sciences 90(2), 296-3003 (2006)
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Session 3: Detection and Characterization of Nanomaterials in the Environment
Mr. John Scalera -- Presentation Slides 139
NANOTECHNOLOGY AND OSWERNew opportunities and challenges
July 12-13, 2006 Washington DC
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